摘要:
A system and method for increasing transmission distance and/or transmission data rates using tedons and an encoding scheme to reduce the number of ones in a data signal is described. For example, the method for increasing transmission distance and transmission data rate of a fiber optical communications link using tedons includes the steps of encoding a data signal to be transmitted using an encoding scheme that reduces a number of ones in the data signal, transmitting the encoded data signal over the fiber optical communications link, receiving the encoded data signal and decoding the encoded data signal.
摘要:
A system and method for increasing transmission distance and/or transmission data rates using tedons and an encoding scheme to reduce the number of ones in a data signal is described. For example, the method for increasing transmission distance and transmission data rate of a fiber optical communications link using tedons includes the steps of encoding a data signal to be transmitted using an encoding scheme that reduces a number of ones in the data signal, transmitting the encoded data signal over the fiber optical communications link, receiving the encoded data signal and decoding the encoded data signal.
摘要:
This invention provides a new architecture for a communication system between head-ends and end-users which expands bandwidth and reliability of the communication system. A mux-node receives communication signals from a head-end and forwards the received communication signals to one or more mini-fiber nodes. The connection to the head-end is via a small number of optical fibers and the connections to each of the mini-fiber nodes may be via one or more optical fibers that may provide full duplex communication. The head-end may communicate with the mux-node using digital or digital and analog signals. The mini-fiber nodes may combine the signals received from the head-end with loop-back signals used for local media access control prior to forwarding the signals to the end-users. Upstream data are received by the mini-fiber nodes and transmitted to the mux-node. The mux-node may route upstream communication signals received from the mini-fiber nodes as downstream signals to other mini-fiber nodes also connected to the mux-node without head-end interaction.
摘要:
A method and system for generating and transmitting optical signals with only one sideband. Single-sideband optical signal transmission reduces the signal impairment effects associated with dispersion. Such transmission also increases the spectral efficiency of optical transmission systems. Single-sideband modulation also makes possible electrical compensation for optical link dispersion during transmission. Single-sideband modulation is generated using the modulating data signal and its Hilbert transform, which is approximated by a tapped-delay time filter. Line coding is used to remove the low-frequency content in the modulating data signal, avoiding the inefficiencies of tapped-delay-line filter approximated Hilbert transformers at low frequencies. Line coding can also help optical single side band signal generation and transmission using a simple optical filter instead of Hilbert transformers.
摘要:
Methods and apparatus are provided for transmitting alternate-polarization phase-shift-keyed data. The output of a laser is modulated to optically encode electronic data using phase shift keying (PSK) to generate an optical signal. An alternate polarization PSK (APol-PSK) signal is generated by alternating the polarization of the optical signal using a modulator such that successive optical bits have substantially orthogonal polarizations.
摘要:
A bi-directional optical transmission system provides communications between at least two locations over a single optical fiber. The transmitters at the respective locations are defined to have different optical spectra characteristics to avoid production of optical beat interference.
摘要:
An apparatus and method for providing dispersion compensation for chromatic dispersion introduced in the signal conversion of an optical signal. An exemplary apparatus in accordance with the present invention includes a nonlinear conversion medium arranged within an optical signal path of the optical signal. The conversion medium receives the optical signal and generates a converted optical signal therefrom. At least one dispersion compensator is arranged within the signal path to provide an amount of chromatic dispersion suitable to offset a portion of the chromatic dispersion introduced in the converted signal by the nonlinear conversion medium. The nonlinear medium may be a length of dispersion-shifted fiber used to phase conjugate and/or frequency shift an input optical signal in an optical system utilizing, for example, optical phase conjugation to cancel the effects of fiber nonlinearities. The dispersion compensator may be placed in the optical signal path either before or after the nonlinear conversion medium, or may be distributed within the medium.
摘要:
A space division multiplexed (SDM) transmission system that includes at least two segments of transmission media in which a spatial assignment of the two segments is different is provided. For example, the SDM transmission may include a first segment of transmission media having a first spatial assignment and a second segment of transmission media having a second spatial assignment, wherein the first spatial assignment differs from the second spatial assignment. An example method obtains an optical signal on a first segment of transmission media having a first spatial assignment and forwards the optical signal on a second segment of transmission media with a different spatial assignment. The transmission media may be a multi-core fiber (MCF), a multi-mode fiber (MMF), a few-mode fiber (FMF), or a ribbon cable comprising nominally uncoupled single-mode fiber (SMF).
摘要:
A method of multiple-band switching using a multi-pump fiber parametric switch is demonstrated. The switching architecture combines parametric band amplification, wavelength conversion and selective signal conjugation, enabled by temporal control of at least one pump of the multi-pump parametric device. The switching speed of the present invention is limited by the rise time of the controlled pump(s).
摘要:
Link robustness, chromatic dispersion and polarization mode dispersion (PMD) immunity can be improved in fiber optical system by using a method for receiving an optical double sideband signal over an optical fiber system, comprising the steps of splitting the received optical double sideband signal into an upper sideband signal and a lower sideband signal, photodetecting the upper sideband and the lower sideband, equalizing the photodetected upper sideband signal and the lower sideband signal, and combining the equalized upper sideband signal with the equalized lower sideband signal. While PMD compensation is envisioned as a major application, one may also use the method and system for chromatic dispersion compensation or dispersion slope compensation in high bit rate systems, i.e. using dispersion compensation fiber (DCF) for coarse compensation and diversity receiver with electrical equalizer for fine tuning.